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Currently, sufficient data are available on the negative impact of the COVID-19 pandemic and its socio-economic consequences on human mental health and the mental ecology in general. The success of public health strategies to cope with pandemics is largely determined by psychological factors and the mental values prevailing in the community at large. The present review systematized the psychological response features of various social, professional, and national representatives during the COVID-19 period within the framework of the main mental ecology provisions. The review methodology was based on the World Health Organization documents and open sources of the Scopus and Web of Science databases on the population's mental health under COVID-19 pandemic conditions. A significant increase in adaptive and anxiety-depressive disorders was noted during the COVID-19 pandemic. Among the specific mental phenomena associated with the pandemic, coronaphobia, COVID-19-stress syndrome, covid-dissidence manifestations with the involvement of conspiracy theories, and mythological thinking were identified. The negative infodemia impact on the mental ecology, as well as the adherence to anti-epidemic measures and readiness for vaccination, were also established. Negative trends were demonstrated in communities where the maximum infection and death risk were associated with low adherence to the epidemiological measures and refusal to vaccination. It was revealed that belonging to certain social or professional groups largely determines a person's behavior in relation to a new coronavirus infection within the framework of accepted social norms. Based on the analysis of a large domestic and international data number on the impact of the COVID-19 pandemic emergency on the human psyche, its significant adverse contribution to the overall mental ecology was noted. The necessity of developing special therapeutic and psycho-prophylactic programs aimed at coping with the stress pandemic impact and treatment of affective disorders, countering infodemia, and strengthening behavioral patterns to maintain mental health and personal well-being is substantiated.

The article aims at studying the legal nature and essence of local self-government bodies in the Russian Federation as exemplified by the theoretical and legal comprehension of the historical aspects of forming local self-government bodies. The article uses the methods of induction and systemic scientific analysis, as well as comparative-legal and historical methods. The authors of the article proved that the implementation of the principles of local self-government in the Russian state apparatus became effective since it is based on objective economic, political and social prerequisites and conditions. As a result, all cities and rural settlements became municipalities.Keywords: Local self-government; Constitution; Municipal authority; Municipal structure; Human rights. Badan Pemerintahan Lokal di Rusia: Kebijakan Pembentukan dan Pengembangan AbstrakArtikel ini bertujuan untuk mempelajari sifat hukum dan esensi dari badan-badan Pemerintahan Lokal di Federasi Rusia, sebagaimana yang dicontohkan oleh pemahaman teoretis dan hukum dari aspek-aspek sejarah pembentukan badan-badan pemerintahan lokal sendiri. Artikel ini menggunakan metode induksi dan analisis ilmiah sistemik, serta metode komparatif-hukum dan historis. Penulis artikel membuktikan bahwa penerapan prinsip-prinsip pemerintahan lokal sendiri di aparatur negara Rusia menjadi efektif karena didasarkan pada prasyarat dan kondisi ekonomi, politik dan sosial yang objektif. Akibatnya, semua kota dan pemukiman pedesaan menjadi kotamadya.Kata Kunci: Pemerintahan Daerah Lokal; Konstitusi; Otoritas Kota; Struktur Kota; Hak Asasi Manusia.Органы местного самоуправления в России: Политика формирования и развития АннотацияСтатья направлена на изучение правовой природы и сущности органов местного самоуправления в Российской Федерации на примере теоретико-правового осмысления исторических аспектов формирования органов местного самоуправления. В статье используются методы индукции и системного научного анализа, а также сравнительно-правовой и исторический методы. Автор статьи доказал, что реализация принципов местного самоуправления в российском государственном аппарате стала эффективной, поскольку основывается на объективных экономических, политических и социальных предпосылках и условиях. В результате все города и сельские поселения стали муниципалитетами.Ключевые слова: Местное самоуправление; Конституция; Муниципальная власть; Муниципальное устройство; Права человека.

Global navigation satellite systems (GNSSs) are widely used for navigation and timing. However, GNSS receivers are vulnerable to jamming, spoofing, line‐of‐sight blockages, and multipath reflections in urban environments and under dense foliage. This chapter introduces the most popular GNSS augmentation approach, which is integration with an inertial navigation system (INS). It reviews the main principles of inertial navigation and develops basic INS error propagation models, respectively. The chapter describes loosely, tightly, and deeply coupled navigation mechanization. It then presents two case studies that include GNSS/INS integration for urban navigation, which includes the use of consumer‐grade micro‐electromechanical systems inertial sensors, and deep integration for navigation in dense forestry areas. The main goal of GNSS/INS integration is to enable a navigation mechanization that combines their benefits while eliminating drawbacks.

Older people and their families were particularly affected during the COVID-19 pandemic in 2020, but not much is known about the context of the Arctic regions of Russia. In this study, we identified the changes in family care before and during the pandemic using a questionnaire for the informal caregivers of older people. We investigated how and to what extent the pandemic has affected the relationships between caregiver and older person, and how the mental and physical health of older people and caregivers were affected by self-isolation in the Arkhangelsk region of Russia. The pandemic has changed the contribution of care from various actors: the share of care by charities, churches, and other aid agencies increased, while that of municipal services decreased. Sixteen percent of female and forty percent of male caregivers informed the study that COVID-19-related restrictions led to deterioration in the health of older people cared for at home. Family caregivers' own health worsened, especially mental health: 28% of caregivers reported aggravated stress during the COVID-19 pandemic and expressed various fears. Our data show that the main resources in overcoming the period of self-isolation have been telephone communication, personal contact, reading/music, friends, as well as the help of social services and maintaining a positive attitude.

This international guideline proposes improving clozapine package inserts worldwide by using ancestry-based dosing and titration. Adverse drug reaction (ADR) databases suggest that clozapine is the third most toxic drug in the United States (US), and it produces four times higher worldwide pneumonia mortality than that by agranulocytosis or myocarditis. For trough steady-state clozapine serum concentrations, the therapeutic reference range is narrow, from 350 to 600 ng/mL with the potential for toxicity and ADRs as concentrations increase. Clozapine is mainly metabolized by CYP1A2 (female non-smokers, the lowest dose; male smokers, the highest dose). Poor metabolizer status through phenotypic conversion is associated with co-prescription of inhibitors (including oral contraceptives and valproate), obesity, or inflammation with C-reactive protein (CRP) elevations. The Asian population (Pakistan to Japan) or the Americas’ original inhabitants have lower CYP1A2 activity and require lower clozapine doses to reach concentrations of 350 ng/mL. In the US, daily doses of 300–600 mg/day are recommended. Slow personalized titration may prevent early ADRs (including syncope, myocarditis, and pneumonia). This guideline defines six personalized titration schedules for inpatients: 1) ancestry from Asia or the original people from the Americas with lower metabolism (obesity or valproate) needing minimum therapeutic dosages of 75–150 mg/day, 2) ancestry from Asia or the original people from the Americas with average metabolism needing 175–300 mg/day, 3) European/Western Asian ancestry with lower metabolism (obesity or valproate) needing 100–200 mg/day, 4) European/Western Asian ancestry with average metabolism needing 250–400 mg/day, 5) in the US with ancestries other than from Asia or the original people from the Americas with lower clozapine metabolism (obesity or valproate) needing 150–300 mg/day, and 6) in the US with ancestries other than from Asia or the original people from the Americas with average clozapine metabolism needing 300–600 mg/day. Baseline and weekly CRP monitoring for at least four weeks is required to identify any inflammation, including inflammation secondary to clozapine rapid titration.

Purpose: The purpose of the study is to analyze the structure of mental disorders and social adaptation in retired ex-combatants of the security forces. Methods: 111 retired men, ex-combatants who sought medical care, were examined. There are two groups: I: 56 people with identified mental disorders; II: 55 with pre-nosological mental health disorders. Results: It is shown that the state of mental health of retired ex-combatants is characterized by severe polymorphic mental disorders, especially those expressed in group I (organic, behavioural disorders, substance use, schizophrenia, schizotypic and delusional disorders, affective, neurotic, stress-related, and somatoform disorders, personality and behaviour disorders in adulthood), as well as social maladaptation, associated with the transformation of values, lifestyle and communication, the emergence of difficulties in social and everyday life, the breakdown of social ties and the displacement of pensioners from public life. Conclusion: The article substantiates the need for a comprehensive approach to the rehabilitation of retired ex-combatants with the interaction of all government structures, public associations, medical, psychological and social institutions directly related to the development and implementation of individual rehabilitation routes.

With a single antenna, it is rather difficult to discern an authentic GPS signal from a spoofing signal merely based on the time-domain waveforms especially when the two signals are off only slightly in time, frequency, and phase. The root-cause of vulnerability of all conventional GPS receivers to power-dominant creep-in spoofing attacks is their “myopic” architecture, which has only three correlators and cannot “see” far beyond ±1.5 chips until too late. When the spoofing signal is on top of the authentic signal, their summation moves the code and carrier error discriminators in a way similar to multipath except that one is location-dependent (multipath) while the other is persistent (spoofing). The fact is that the presence of a spoofing signal cannot eradicate the existence of an authentic signal even though it may overpower the latter. If a spoofing signal always aligns itself to the authentic signal, no harm is done. When a spoofing signal captures a receiver and starts to pull away, two correlation peaks will emerge in the time-frequency domain, one belonging to the spoofing signal and the other to the authentic signal. This fact has been used in the past for spoofing detection. In this paper, we go one step further to develop an all signal acquisition processing (ASAP) scheme that not only mitigates the effect of spoofing but also estimates the spoofing signal for spoofing intent analysis. This paper first details a spoofing simulator implementation that enables high-fidelity software-based injection of spoofing signals into live-sky GPS RF signal data. The ASAP scheme is then described, which provides a range protection level better than 1 chip (300 m) with the conventional correlator architecture. Similarly, the signals can also be separated at the output of 20 ms correlations if off in frequency by 25 Hz. Higher range protection level and tighter spectral separation are possible for a modified architecture. Simulation results are presented to illustrate the functionality and performance of spoofing detection, estimation, and mitigation.

The binary offset carrier (BOC) modulation was initially developed for easy sharing of spectrum between GPS modernization signals and legacy binary phase shift keying (BPSK)-modulated signals in the same band. It is now adopted by all GNSS constellations as a BOC signal has a larger Gabor bandwidth, producing better ranging (accuracy and multipath) performance. However, general BOC signal acquisition and tracking encounters the problem of multiple peaks (less an issue for MBOC, though), and many methods have been proposed to address this issue. A simple method to avoid such an ambiguity is to extract the upper and lower sidebands of the split spectrum of a BOC signal, treat them separately as a BPSK signal each, and then combine the results so as to recover the reduced sideband signal strength. Coherent combining is more gainful than the noncoherent counterpart particularly when the incoming signal is weak and/or when a strong interference signal is present. In this paper, a long coherent combining and integration (LCCI) scheme is presented, which enables standalone acquisition of a BOC signal without external aiding from a network or an inertial navigation system (INS) under combined narrowband and matched spectral interference signals. The LCCI scheme burns through the strong interference via building up the desired signal while averaging out noise and interference. To build up the desired signal, it makes use of all information resources available (e.g., L1 and L2, upper and lower sidebands, odd and even chips, and/or I and Q components) and applies coherent combining and long coherent integration, followed by non-coherent accumulation if necessary. Issues and enabling techniques are presented in this paper. The LCCI scheme is implemented on a software defined receiver (SDR) platform consisting of FPGA and ARM. Results of real-time demo with input RF signals generated by a Spirent GPS Simulator are described in the paper.

This paper presents field test results of mobile positioning with signals of opportunity (SOOP) in urban and urban canyon environments and the lessons learned. The particular SOOP considered in this paper is the digital television (DTV) signals available in the United States, namely, ATSC-8VSB. The field tests include runs in downtown San Mateo and San Francisco Financial District, representing typical urban and urban canyon environments. DTV signals from six DTV stations together with IMU and GPS data are recorded aboard a ground vehicle. The field tests show that DTV signals are abundant in urban and urban canyon environments, contrary to a popular concern about signal availability due to blockage by high-risers. Positioning geometry is also not a problem even though the number of transmitters may be limited because the ranges to signal sources are relatively short and the resulting geometric dilution of precision (GDOP) is acceptable especially for the two-dimensional solutions. However, multipath is omnipresent, having two detrimental effects on ranging and positioning. Severe mobile fading is frequent that disrupts continuous tracking and non-line of sight (NLOS) signals introduce large errors to correlation peak based timing. To process multipath-dominant signals, a signal parameter estimation methodology is developed. In this approach, periodic signal patterns (field sync segments at 41 Hz) are searched for via correlation using a constant false alarm rate (CFAR) detector and their times of arrival (TOA) are extracted using the orthogonal matched pursuit (OMP) algorithm amidst multipath to form pseudorange measurements. Both standalone SOOP solutions and integrated SOOP/IMU solutions are generated for the test trajectories, which are then compared to GPS for performance evaluation. The study indicates that the processing algorithms presented in the paper can successfully detect the first arrival of SOOP in urban and urban canyon environments and extract its TOA precisely when the signals are available (out of fading or blockage). However, the timing information carried by such first arrivals, good enough to serve the primary purpose of communications, may not be so for ranging because of NLOS. As such, timing of first arrivals is not sufficient by itself for positioning and has to be used in conjunction with other data such as IMU, which is used in this paper. Yet, distinct and stable multipath signatures may be exploited, together with an environment map for instance, for persistent positioning in urban and urban canyon environments, which is a direction of our future research.

A multitude of GNSS signals are transmitted at the same frequency band, and even the same signal may have several components with different codes. For examples, different signals are modulated onto the in-phase and quadrature components (e.g., L1C-I and L1C-Q, I5 and Q5) and are time-division multiplexed (e.g., odd and even chips of M-code). Most of these signals adopt the binary offset carrier (BOC) modulation and thus have a split-spectrum as compared to the legacy signals that use binary phase shift keying (BPSK) and have a dominant lobe at the band center. BOC is used not only for the ease of spectrum sharing but also for its improved ranging performance due to a larger Gabor bandwidth. Both weak signals and in particular the presence of strong interference lead to an effective signal to noise ratio (SNR) that is very low. To pull such a signal out of noise and interference, it is necessary to combine multiple signal components available at the same time and then integrate them over time so as to add up the signal strength while averaging the noise and interference out in a burn-through process. However, it is not straightforward to apply the linear additive coherent operation due to the difference in phase and frequency between signal components as well as the presence of unknown data bits, which may become counterproductive if not treated properly. In this paper, we investigate several nonlinear multiplicative schemes including non-coherent, semi-coherent, and cross-conjugate-multiply for signal accumulation (combining and integration), and compare them to the coherent scheme. The study shows that according to the SNR definition at the output of nonlinear operations, some of the schemes may have the same SNR level per analysis of second-order statistics, yet they exhibit different Pd vs. Pfa characteristics, which can be attributed to different distribution tail behaviors (higher order statistics). Understanding of the detection performance is thus important in trading off combining and integration schemes for implementation. Extensive computer simulation results are presented to illustrate the functionality and performance of the schemes.

Background Alcohol drinking is an increasingly recognized risk factor for cardiovascular disease. However, there are few studies of the impact of harmful and hazardous drinking on biomarkers of myocardial health. We conducted a study in Russia to investigate the impact of heavy drinking on biomarkers of cardiac damage and inflammation. Methods and Results The Know Your Heart study recruited a random sample of 2479 participants from the population of northwest Russia (general population) plus 278 patients (narcology clinic subsample) with alcohol problems. The general population sample was categorized into harmful drinkers, hazardous drinkers, nonproblem drinkers, and nondrinkers, according to self‐reported level of alcohol consumption, whereas the narcology clinic sample was treated as the separate group in the analysis. Measurements were made of the following: (1) high‐sensitivity cardiac troponin T, (2) NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide), and (3) hsCRP (high‐sensitivity C‐reactive protein). The narcology clinic subsample had the most extreme drinking pattern and the highest levels of all 3 biomarkers relative to nonproblem drinkers in the general population: high‐sensitivity cardiac troponin T was elevated by 10.3% (95% CI , 3.7%–17.4%), NT ‐pro BNP by 46.7% (95% CI , 26.8%–69.8%), and hsCRP by 69.2% (95% CI , 43%–100%). In the general population sample, NT ‐pro BNP was 31.5% (95% CI , 3.4%–67.2%) higher among harmful drinkers compared with nonproblem drinkers. Overall, NT ‐pro BNP and hsCRP increased with increasing intensity of alcohol exposure (test of trend P Conclusions These results support the hypothesis that heavy alcohol drinking has an adverse effect on cardiac structure and function that may not be driven by atherosclerosis.

The aim of our study was to determine a complex of risk factors of the perimenopausal melatonin deficiency syndrome (SPDM) in postmenopausal women and women during menopausal transition suffering from climacteric syndrome. The study involved 278 women. They were divided into two groups: I group included 246 menopausal women and II group included 32 women during the menopausal transition. The Medical History was collected, the menopausal index, and anthropometric measures were determined. The study was conducted with a help of the test questionnaire for melatonin deficiency (TQMD), the women’s health questionnaire (WHQ), and detection of the level of 6- sulfatoxymelatonin (6-SOMT) in urine. According to the obtained data, risk factors of SPDM in women during the menopausal transition are the chronological age increment, overweight, and the reduction of the estradiol level. The leading risk factors of SPDM in postmenopausal women are the chronological age increment, overweight with visceral type of obesity and changes in the hormonal profile. Thus, SPDM is a new clinical and laboratory marker of aging of the female reproductive system, an important screening tool for detecting the development of CC in women during the menopausal transition and menopausal women.

Correlation at an intermediate frequency (IF) produces a composite correlation function of an envelope being that of the underlying code and an internal structure being that of the IF carrier. By varying the IF, one can introduce zero-crossings to the envelope so as to shape and sharpen the main peak. Such a variable peak is desired for accurate timing of the direct signal while isolating close-in multipath and spoofing signals. The functionality of variable IF correlation in acquisition and its multipath performance are analyzed in a recent paper published in this journal. In this paper, the details of an implementation of variable IF tracking loop are presented with a theoretical background analysis. A publically available open-source software GPS receiver (SOFTGNSS V3.0) is modified into variable IF tracking loop and tested on real-world GPS C/A-code signals. The preliminary test results demonstrate increased code tracking accuracy as well as increased positioning performance.

Relative positioning of networked platforms is a key technical enabler for many missions particularly in environments where GPS is challenged or denied. Collaborative navigation of such networked platforms makes use of relative range, range rate, and/or bearing measurements to each other and/or to a third party so as to improve the relative positioning accuracy and possibly the absolute one. A centralized processing scheme, which gathers all measurements from all nodes and then disseminates the processing results, though being theoretically optimal, is not scalable as the network size increases. Besides, it presents the risk of a single point failure. A distributed decentralized estimation strategy, though suboptimal, is practical. The navigation states of active nodes in the network are communicated to a node via data link and those neighboring nodes that are involved in common view and/or internodal sensing are used in assisting the node to improve its navigation. However, each distributed estimator needs to take into account the uncertainty of the assisting states. In addition, the use of common view and/or inter-nodal measurements, though not dynamically coupled, makes their state estimation errors correlated. This cross-correlation, if not accounted for properly, would make the estimation too optimistic (inconsistent) and may lead to divergence (de-weighting and discarding new measurements). The adjacent nodal uncertainty and inter-nodal cross-correlation are two major issues to address for a viable scalable distributed estimation mechanization. In this paper, we perform a theoretical analysis of inter-nodal rank-1 updating. The behavior of collaborative navigation with inter-nodal measurements differs from a standalone navigation with similar measurements to a reference point. It is shown that the error reduction is not symmetric for collaborative navigation, depending on relative errors of each node. The direction of minimum error of a node can serve as a reference for others with large errors in that direction, which has implications in sensor selection and/or path planning. Furthermore, there is an initial error reduction when two nodes first communicate (a teamwork effect due to spatial averaging) and no further reduction afterwards due to cross-correlation (a reset effect without temporal averaging). However, as the agents propagate in space and time, their state estimates become de-correlated due to inertial error growth and local updates with different sensors. At this point, inter-nodal updating becomes more cost-effective again. Simulation results are presented to support the analyses with discussion on implications for algorithm design and implementation.

The binary offset carrier (BOC) modulation is used in many GNSS signals, not only for its facility for spectrum sharing but also for improvement of ranging performance due to a larger Gabor bandwidth. However, BOC signal acquisition and tracking encounters the ambiguity of multiple peaks and many methods have been proposed to address this problem. A simple method to avoid such an ambiguity is to extract the split spectra, treat them separately as BPSK signal each, and then combine the results. To recover the reduced sideband signal strength, the individual sideband correlations are combined non-coherently or coherently. Coherent combining is more gainful than the non-coherent counterpart particularly when the incoming signal is weak or when a jamming signal is present. Direct long coherent integration (LCI) requires a fine frequency search grid, which would be prohibitive if the frequency search were implemented by brute force. Alternatively, a two-stage approach seems efficient and practical. It starts with a first stage of short correlation for coarse search, followed by a second stage of coherent integration with refined search. In addition to dealing with unknown navigation data bits that change sign during the long integration interval, phase-alignment is required to compensate for code migration and frequency divergence, which are two detrimental effects unique to split-spectrum signals integrated over a long period of time. In this paper, a two-stage method for standalone direct acquisition of weak multi-band split-spectrum signals is described. By standalone, we mean absence of any external aiding, say, from a network or an inertial navigation system (INS). By direct, we mean the acquisition procedure without going through legacy codes. The proposed method makes judicious use of coherent and non-coherent integrations with time and frequency adjustments so as to maximize the combining of data-modulated and dataless (pilot) chips, upper and lower sideband signals, and signals on different frequencies. Issues and enabling techniques are described. Extensive computer simulation results are presented to illustrate the functionality and performance of the method.

The drug situation monitoring system in Russia uses data on the number of drugs withdrawn from circulation in a weight indicator. However, this does not reflect the real extent of the danger, since differences in the activity of substances and population density of different administrative districts are not taken into account. Based on the analysis of statistical data, a methodology for calculating the prevalence of drugs based on the determination of conventional doses that are multiples of the size of the narcotic drugs, determining the onset of criminal liability and determining their prevalence in the territory of the administrative district per 100,000 population is proposed. Keywords:Narcotic drugs; Methodology for calculating seized psychoactive substances; Drug situation; Drug monitoring

In order to analyze the self-assessment of mental health status of combatants, a year after the execution of operational and service tasks in special conditions, a complete survey of 964 combatants was conducted, which were divided into three groups by level of mental health: Group I - 338 people – healthy combatants who were not provided with rehabilitation assistance; Group II - 311 persons who for 6 years prior to the survey, according to the outpatient cards revealed prenosological neurotic conditions, clinical data on the presence of borderline mental disorders (BMD) after returning from combat zones in this group was not revealed, they were provided with short-term psycho-correctional assistance by psychologists at the place of service; Group III – 315 people who were diagnosed with adaptation disorders (AD) and post-traumatic stress disorder (PTSD), in this regard, they were treated and medical & psychological rehabilitation. A year after the events, a clinical examination and a questionnaire were conducted. It is shown that the mental state of combatants with BMD is characterized by the absence of clinical symptoms, which indicates the effectiveness of the activities. Given the fact that persons who did not receive psycho-prophylactic and rehabilitation aid, a year after participating in the fighting are identified psychosomatic disorders and specific psychopathological symptoms, we have proposed the improvement of methodological approaches to providing them with psychoprophylactic assistance with the development of legislative regulation of complex rehabilitation measures. Keywords:Combatants; Mental disorders; Self-assessment; Stages of rehabilitation

For vision-based navigation applications, the assumption of a Gaussian distribution for measurement errors may not be valid due to outliers commonly resulting from complicated algorithmic processing of images (for example, feature extraction, feature matching, and frame-to-frame tracking). Although many algorithms have been developed to minimize the probability of outputs that are outliers, the probability is still nonzero and is not estimated with current approaches. This paper develops a vision-aided inertial navigation mechanization that explicitly accounts for the presence of outliers in vision measurements. Navigation mechanization is augmented by probabilistic data association filtering. Probabilistic data association filtering takes into account nonperfect detection of outliers by adaptively computing the probability that an outlier is undetected and weighting vision measurements accordingly. Simulation and experimental results are used to demonstrate that the probabilistic data association filteri...

Positioning with signals of opportunity (SOOP) encounters two major technical challenges in urban mobile environments, namely, multipath and clock errors. The presence of signal fading, multipath dominance over direct signal, and non-line of sight (NLOS) signal can occur more than 50% of the time, as evident in the experimental data presented in this paper. As such, conventional delay lock loop (DLL) based on correlation peak tracking can be easily destabilized. As a remedy, we set forth a first arrival estimation method based on the constant false alarm rate (CFAR) detection and matching pursuit (MP) algorithm, which is shown to provide better pseudorange measurements. Furthermore, not all commercial signals of opportunity strictly align their clock to a stable frequency reference such as the GPS atomic time but rather may apply local frequency adjustment on their own. Such an adjustment may result in higher order oscillatory clock errors. We propose to use a six-state Kalman filter to calibrate both quadratic and sinusoidal error terms so as to prevent long-term pseudorange divergence and error growth in the position solutions. Finally, we present experimental data illustrating standalone and inertial-integrated position solutions to demonstrate the performance of urban mobile positioning with mixed signals of opportunity (digital television and cellular phone signals).

In vision-aided navigation, images from natural scenes are processed by a chain of complicated algorithms from feature extraction, feature matching, to frame-to-frame tracking to produce vision measurements for navigation aiding. Such vision measurements are subject to non-Gaussian errors and in particular outliers, which, if not properly accounted for, lead to inconsistent, usually optimistic, estimation. The Assured Vision-Aided Inertial Localization (AVAIL) mechanization is recently set forth, which augments the inertial navigation with the probabilistic data association filtering (PDAF) that adaptively computes the probability that an outlier is undetected and weights vision measurements accordingly. Based on a rather general assumption about the outlier distribution, the AVAIL mechanization is shown to be consistent in the presence of real-world image processing errors. In this paper, we study feature matching errors and especially the circumstances in which outliers occur. We do this by checking the extracted features and detected outliers against the original images in the real-world environments so as to verify spatial and temporal assumptions about the feature errors and their distributions. The study shows evidences that lend a strong support to the AVAIL mechanization.

International audience; In general, the carrier phase of orthogonal frequency division multiplexing (OFDM) signals is not tracked for at least two reasons. First, the dc component of most baseband OFDM symbols is a null subcarrier so as to avoid the effect of dc bias at reception. Second, generation and transmission of OFDM symbols are independent from one symbol to next. As a result, no phase continuity is required to be maintained at any subcarriers. For communications, demodulation of OFDM symbols with cyclic prefix (CP) is tolerant to small timing errors and insensitive to the absolute phase but relative phase at data subcarriers, which can be easily calibrated with the help of pilot subcarriers. However, the OFDM signaling adopted by the Terrestrial Digital Video Broadcast (DVB-T) retains the dc component. Besides, the CP duration is specified in such a way that a whole number of cycles is ensured for the middle carrier. It happens in DVB- T that the middle carrier is assigned as a continual pilot subcarrier, which has a constant value across OFDM symbols. As a result, the baseband center frequency (dc component) has no phase discontinuity, which gives rise to the opportunity for carrier phase tracking. Carrier phase tracking has the potential to provide more accurate timing for ranging and ultimately for positioning than cross-correlation of CP and pilot subcarriers in coarse and fine time of arrival (TOA) estimation, respectively. In this paper, in-the air DVB-T signals collected in experimental tests are used to show the functionality and performance of DVB-T signal carrier phase tracking.

Correlation at an intermediate frequency (IF) produces a composite correlation function made of an envelope being that of the underlying code and an internal structure being that of the IF carrier. The IF carrier correlation introduces zero-crossings to the code correlation as if it pinches the code correlation envelope at the zero-crossing points, having the effect of creating a main peak and several secondary peaks. The quick decay towards zero-crossings sharpens the main peak, which is desired for accurate timing of the direct signal while isolating close-in multipath and spoofing signals. The functionality of variable IF correlation (VIC) in acquisition and its multipath performance are analyzed in a recent paper, together with its lock onto the main peak among secondary peaks without ambiguity and false lock. In this paper, the implementation of VIC into a variable IF tracking loop (VITAL) is presented. A publically available open-source software GPS receiver is modified into VITAL by simply replacing the conventional correlators using a half-chip spacing with the VIC using a spacing of one eighth cycle of IF. The modified software receiver is then used to demonstrate VITAL on real-world GPS C/A-code signals. The preliminary testing results show an increased code tracking accuracy as well as an increased performance positioning results.

Correlation at an intermediate frequency (IF) produces a composite correlation function, which is made of an envelope being that of the underlying code and an internal structure being that of the IF carrier. The IF carrier correlation introduces zerocrossings to the code correlation as if it pinches the code correlation envelope at the zero-crossing points, having the effect of creating a main peak and secondary peaks. The quick decay towards zero-crossings sharpens the main peak, which is desired for accurate timing of the direct signal while isolating close-in multipath and spoofing signals. Either sequential or parallel use of variable IF correlation (VIC) helps lock onto the main peak among secondary peaks without ambiguity and false lock. In this paper, a zero-padded spectrum translation (ZPST) technique is introduced to enable VIC for baseband signals, which is especially suitable for software-defined radios (SDR) that make use of FFT-implemented correlation and very natural for radio transmissions that specify reference signals in the frequency domain such as pilot subcarriers in OFDM (e.g., Wi-Fi, 4G LTE, and DVB-T). Results of simulation and of processing in-the-air DVB-T data are presented to demonstrate the principle and viability of VIC.